Recently, high performance, miniaturization and lightness of electronic equipment have been fast accomplished along with the development of semiconductor integrated circuit and surface mounting technology for loading small sized chip in the whole industrial field. And, conductive fibers were developed to prevent static electricity of electronic equipment and parts, to absorb microwave, to shield electromagnetic wave, to produce low weight electronic parts and to secure reliable performance.
The conventional conductive fibers are mostly metal fibers such as nickel, copper, stainless steel, aluminum, tin, zinc, antimony and titanium or metal coated fibers produced by coating non-conductive glass fibers or carbon fibers with such metals as nickel, gold, silver, copper and titanium via plating or deposition or sputtering. Korean Patent Publication No. 2003-0022234 and Japanese Patent No. 2001-200470 describe a method of manufacturing conductive fibers, in which a metal seed layer is coated on fibers by sputtering, followed by electroless plating. However, the method described therein has a problem of conductive layer separation because of poor adhesion of the seed layer.
Unlike the method for giving conductivity to fibers by coating inorganic fibers such as metal, glass, carbon and metal oxide with metals, the method for giving conductivity to plastic fibers is characterized by dispersing conductive fillers such as conductive spheres, needle-shaped whiskers and plate type flakes and spinning thereof to make the fillers contact or be close to each other in order to apply electricity effectively (Journal of Applied Physics, 72, 1992). At this time, the conductive filler is selected from the group consisting of metals such as iron, nickel, copper and aluminum; conductive carbon-based materials such as black lead, carbon nano-tube (CNT), carbon fiber and graphite; and a mixture thereof. However, this method has disadvantages of unsatisfactory stability resulted from coagulation or precipitation of the filler included in spinning solution and poor mechanical properties including strength and softness of fibers resulted from high volume ratio of the conductive filler required for giving enough conductivity.